Embodiments of the present disclosure generally relate to systems and methods for establishing a communication link between devices, and more particularly to managing advertising and scanning schedules utilized to establish communication links between implantable medical devices and external instruments.
An implantable medical device (IMD) is a medical device that is configured to be implanted within a patient anatomy and commonly employs one or more leads with electrodes that either receive or deliver voltage, current or other electromagnetic pulses from or to an organ or tissue for diagnostic or therapeutic purposes. In general, IMDs include a battery, electronic circuitry, a pulse generator, a transceiver and/or a microprocessor that is configured to handle communication with an external instrument as well as control patient therapy. The components of the IMD are hermetically sealed within a metal housing.
IMDs are programmed by, and exchange data with, external instruments controlled by physicians and/or the patient. The external instruments use commercial operating systems (e.g., iOS, Android) that communicate through wireless bi-directional communication links with the IMDs. The bi-direction communication link is formed based on advertisement notices received by the external instruments. The advertisement notices are broadcast by the IMD at a predetermined constant frequency based on the wireless protocol. However, the current drain expended by the IMD to broadcast the advertisement notices can be too high where battery life is a concern, particularly in smaller devices that have limited space for batteries. To conserve current drain, it has been proposed to transmit advertisement notices at a lower frequency than defined by the wireless protocol, such as by waiting several seconds or minutes between transmission of successive advertisement notices (e.g., instead of a few seconds or milliseconds).
However, many external instruments have built in constraints related to how long the external instrument will monitor for advertisement notices for usability and power consumption purposes. If an advertisement notice is not received by the external instrument within a predetermined number of monitoring periods, the external instrument may decrease the frequency of the monitoring period. If the external instrument misses an advertisement notice, minutes may pass before the external instrument begins to monitor for an advertisement notice. When multiple unsuccessful monitoring periods occur, the battery of the external instrument is undesirably drained.
Further, today many external instruments use Bluetooth low energy (BLE) to connect to an IMD. The external instrument (EI) may be configured to scan for IMD advertisements with a first duty cycle during a first portion of a scanning interval. For example, the EI may maintain scan windows 50%-60% of the time out of a few hundred milliseconds. When an IMD advertisement is not detected during a scan window within the first scanning interval, the EI continues to scan, but utilizes a slower duty cycle. For example, during a second scanning interval, the EI may maintain scan windows open only during 25%-30% out of the same period of a few hundred milliseconds. Accordingly, when a connection is not made early in the EI scanning process, an unduly long period of time may occur before an IMD advertisement overlaps with an EI scanning window.
In accordance with the foregoing, conventional BLE telemetry protocols causes an undue drain on the IMD battery. The drain occurs when the EI does not connect with the IMD during the first scanning interval (within scan Windows are opened more frequently). The IMD then has to advertise for a longer period of time. Currently, the usage of the EI BLE Application program interface (API) results in an inconsistent connectivity to the IMD even among devices utilizing the same operating system (OS). A need exists for improved methods and systems to manage a communication link between the external instrument and an IMD.